ledger board

huangyhg

ledger board
i am designing some floor joists that will be perpendicular and adjacent to a concrete retaining wall.  the joist can be top flange mounted to a sill plate ontop the retaining wall.  question:  is there a code which tells me that i would have to use a ledger board between the joist ends and the retaining wall?  (is it 1 inch min?).
i do not know of a code restriction about supports for wood joists, but "what is not prohibited is permitted" and with good engineering judgement i am going to suggest an option.
i ran into this type of situation for a residential project and working with a contractor who asked for a practical solution we came up with a ledger bolted to the concrete wall, say @ 4'-0" o.c. ,(also perpendicular to the floor joists) and then your joists can be either nailed or secured with joist hangers to the ledger.
hope it helps to come to a solution to your particular issue.
regards
chicago rarebug
thanks - i'll probable do that.  i may also incorporate a bolster towards the top of the retaining wall, and use it for a "seat."
if you are attaching the ledger to the concrete with bolts and taking all the load in shear, you will probably need bolts closer than 4 ft o.c. if your joist span is 8 ft or greater.  4'x4'x50psf=800 lb. which is approximately the allowable shear of a 5/8" bolt supporting 2x lumber.  this is one of the most common errors i see in using bolted on ledger boards.  if you make the pocket in the top of the wall and inset the ledger as tricalcim said then the bolt only has to hold the ledger to the concrete and you don't have the shear problem.  otherwise you usually end up with two rows of bolts at 4' centers or single rows at 2' centers or 3/4" or larger bolts.